1. Technical Field
This disclosure relates to an apparatus and method for the biopsy of tissue specimens and, more particularly to a percutaneous biopsy cutting blade and method.
2. Background of Related Art
It is often necessary to sample tissue in order to diagnose and treat patients with cancerous tumors, pre-malignant conditions and other diseases or disorders. Typically, in the case of suspected cancerous tissue, when the physician establishes by means of procedures such as palpation, x-ray or ultrasound imaging that suspicious conditions exist, a biopsy is performed to determine whether the cells are cancerous. Biopsy may be done by an open or percutaneous technique. Open biopsy removes the entire mass (excisional biopsy) or a part of the mass (incisional biopsy). Percutaneous biopsy on the other hand is usually done with a needle-like instrument and may be either a fine needle aspiration (FNA) or a core biopsy. In FNA biopsy, individual cells or clusters of cells are obtained for cytologic examination and may be prepared such as in a Papanicolaou smear. In core biopsy, as the term suggests, a core or fragment of tissue is obtained for histologic examination which may be done via frozen section or paraffin section.
The type of biopsy utilized depends in large part on the circumstances present with respect to the patient and no single procedure is ideal for all cases. Core biopsy, however, is extremely useful in a number of conditions and is being used more frequently.
Intact tissue from the organ or lesion is required by medical personnel in order to arrive at a definitive diagnosis regarding the patient's condition. The tissue extracted must be indicative of the organ or lesion as a whole. In the past, to obtain tissue from organs or lesions within the body, surgery had to be performed in order to locate, identify and remove the tissue. With present technology, medical imaging equipment such as x-rays, fluoroscopy, computer tomography, ultrasound, nuclear medicine and magnetic resonance imaging, may be used. These technologies make it possible to identify small abnormalities even deep within the body. However, definitive tissue characterization still requires obtaining adequate tissue samples to characterize the histology of the organ or lesion.
In the example of breast cancers, mammography can identify non-palpable (not perceptible by touch) breast abnormalities earlier than they can be diagnosed by physical examination. Most non-palpable breast abnormalities are benign but some are malignant. When breast cancer is diagnosed before it becomes palpable, breast cancer mortality can be reduced. It is still difficult to determine if pre-palpable breast abnormalities are malignant, as some benign lesions have mammographic features which mimic malignant lesions and some malignant lesions have mammographic features which mimic benign lesions. Thus, mammography has its limitations. To reach a definitive diagnosis, tissue from within the breast must be removed and examined under a microscope.
With the introduction of stereotactic and ultrasound guided percutaneous breast biopsies, an alternative to open surgical breast biopsy became an option. These guidance systems have become more accurate and easier to use than when they were first introduced. Biopsy guns were introduced for use in conjunction with these guidance systems. The biopsy guns were limited because placement of the gun had to be done very accurately because only one small core could be obtained per insertion at any one location. To sample the lesion thoroughly, many separate insertions of the instrument had to be made.
Many biopsy procedures would benefit from larger tissue samples being taken, for example, tissue samples as large as 10 mm across. Many of the previously developed devices required multiple punctures into the breast or organ in order to obtain the necessary samples. This practice is both tedious and time consuming.
One further solution to obtain a larger tissue sample is to utilize a device capable of taking multiple tissue samples with a single insertion of an instrument. An example of such a device is found in U.S. Pat. No. 5,195,533 to Chin et al. which describes a technique for extracting multiple samples with a single insertion of the biopsy device. Generally, such biopsy instruments extract a sample of tissue from a tissue mass by either drawing a tissue sample into a hollow needle via an external vacuum source or by severing and containing a tissue sample within a notch formed on a stylet. Typical of such devices utilizing an external vacuum source are U.S. Pat. No. 5,246,011 issued to Cailouette and U.S. Pat. No. 5,183,052 issued to Terwiliger. These designs are usually limited in the size of the sample extracted to the outside diameter of the needle or tube in which the tissue sample is to be carried.
It would be advantageous to provide only a small opening in the skin of the breast, but be able to obtain large biopsy samples. Therefore, a need exists for a percutaneous biopsy apparatus and method which can extract a biopsy sample larger than the skin opening in the patient through which it must be drawn.